Numerous devices of varying types and sizes are known to generate and emit electromagnetic radiation. Many of these devices have a unique combination of components and mechanical properties that distinguish their respective radio frequency (RF) emissions from those of another device. For example, considering devices such as vehicles, those of the same make and/or model are known to have varying electromagnetic emissions based on transients generated by the vehicle electrical system, the vehicle geometry, and signals produced by the vehicle's electronic components such as electronic systems that incorporate high-speed digital logic such as microprocessors and their associated components, and electronic chopper circuits used for lamp dimming or motor speed control.
US 2011/0267222 discloses a vehicle detection system and method used to identify, track, and locate a vehicle by passively sensing RF signals emitted by a target. The system includes an antenna and a processing module. The antenna scans select frequencies of known RF signatures. The processing module compares the scanned RF data to stored template signatures and determines a location of the target emitting the RF. Once the location of the target is determined, it is output to a display or transmitted to another electronic device.